Vestibular System Assessment
Following referral from your medical specialist, we will perform an array of tests able to locate and measure any weaknesses of the inner ear balance system.
Your balance can be affected by a disorder of the inner ear causing unsteadiness or vertigo. A spinning or swaying sensation may result. Untreated, this is a potentially disabling condition. Our dedicated vestibular suite, the only one of its kind in Oxfordshire, allows us to perform a battery of tests that document the full nature of your symptoms – the first step to recovery.
Videonystagmography (VNG) and Calorics
Cameras mounted into a pair of googles will record your eye movements for a classic sign of dizziness known as nystagmus as you track an animated dot on a light bar. Each ear is then stimulated by a small amount of running water to induce a response, the magnitude of which is used to isolate the balance organ at fault.
ICS Head Impulse Testing (HIT)
The head impulse test (HIT) provides quick, clear-cut ear specific assessment of the vestibulo-ocular reflex response to stimuli in the high-frequency range, the natural range of head movements. ICS Impulse from Otometrics is the world’s first HIT device to combine gold-standard accuracy with unrivaled patient comfort, enabling you to perform head impulse testing with inarguable results.
The clinician stands before the patient, holding the patient’s head in his hands, and the patient, who is looking straight at the clinician, is asked to keep staring at the earth-fixed target (the clinician’s nose). If the clinician now turns the patient’s head abruptly and unpredictably to the left or right, through a small angle (only 10-20 degrees – not a large angle), that head turn is what we call the head impulse. If the patient has a functioning vestibulo-ocular response they will be able to maintain gaze on the target because the vestibulo-ocular response drives the eyes to rotate to exactly compensate for head rotation and so maintain fixation.
However if the patient’s vestibulo-ocular response is inadequate then their eyes will be taken off target during the head rotation, because their eyes will not rotate at the correct speed to exactly compensate for head rotation. So an inadequate VOR means that the eyes go with the head during the passive unpredictable head turn and will be taken off target by the head turn, so that at the end of the head turn the patient must make a corrective saccade back to the clinician’s nose. To the clinician watching the patient’s eyes, this saccade is usually very clear, and we have termed it an overt saccade. It is the tell¬tale sign of inadequate semicircular canal function on the side to which the head was rotated. So an overt saccade after a leftwards head rotation means the left semicircular canal has a deficit. If there is any doubt, the clinician just repeats the head impulses until they are satisfied.
Vestibular Evoked Myogenic Potentials (VEMPs)
Vemps are widely accepted as a ‘gold standard’ indicator of certain balance disorders. James Hearing specialists are equipped to provide VEMP testing in addition to the routine vestibular battery.